---
title: Authentication
sidebar_label: Overview
---

## What does it do?

Firebase Authentication provides backend services & easy-to-use SDKs to authenticate users to your app.
It supports authentication using passwords, phone numbers, popular federated identity providers like Google, Facebook
and Twitter, and more.

<YouTube id="8sGY55yxicA" />

## Installation

Before installing the Authentication plugin, ensure that you have followed the [Getting Started](../overview.mdx) documentation
and have initialized FlutterFire.

### 1. Add dependency

Add the [`firebase_auth`](https://pub.dev/packages/firebase_auth) dependency to your projects `pubspec.yaml` file:

```yaml {5} title="pubspec.yaml"
dependencies:
  flutter:
    sdk: flutter
  firebase_core: "^{{ plugins.firebase_core }}"
  firebase_auth: "^{{ plugins.firebase_auth }}"
```

### 2. Download dependency

Download the dependency by running the following command in your project:

```bash
$ flutter pub get
```

### 3. (Web Only) Add the SDK

If using FlutterFire on the web, add the [`firebase-auth`](!firebase_auth) JavaScript SDK to your `index.html` file:

```html {5} title="web/index.html"
<html>
  ...
  <body>
    <script src="https://www.gstatic.com/firebasejs/{{ web.firebase_cdn }}/firebase-app.js"></script>
    <script src="https://www.gstatic.com/firebasejs/{{ web.firebase_cdn }}/firebase-auth.js"></script>
  </body>
</html>
```

### 4. Rebuild your app

Once complete, rebuild your Flutter application:

```bash
$ flutter run
```

## Next Steps

Once installed, you're ready to start using Firebase Authentication in your Flutter Project. View the
[Usage documentation](./usage.mdx) to get started.

<!-- View the [Usage documentation](usage.mdx) to get started. -->
